Im pretty new to woodworking, and i know very little of wood finishes. Im in the tail end of a bathroom remodel and the trim has to be redone because my ex wife painted it blood red. I sanded it all down and got the closest color of stain i could to match the trim in the rest of the house. My question is, is there a stain to match the opacity of the old trim on the right. If not is there any additves that could get me there. Any help is greatly appreaciated

Matching existing looks is a true art. Color, texture, and opacity are all difficult to match and then you have the issue that different lighting conditions (sunlight and artificial lighting) can then change appearance of the pieces.

The good news is that the separation from room to room prevents a direct side by side comparison of the old trim with the refinished trim. I would suggest you try treating sample areas of the backs of the trim pieces until you find a look you are happy with. Stains can often be mixed and darker stains can often reduce the tone. Another thing to consider is that old finishes usually darken and will reduce opacity. Try adding compatible stains or colorants to the finish or using natural amber colored finishes. Colored lacquer has been used to mimic older finishes and different woods for many years and a similar approach might work for you.